I'm doing the same panel with some others for my son's birthday quilt. I'd cut the 'Attic Window' flanges off from the side of the narrow panels and center them. If it still bothers you, make four small blocks for the ends of the narrow panels. Pinwheels or whatever pattern you chose. Log cabins to signify deer camp?
My blocks are not the same size, so that's where I need to start.